Switch



May 5, 1942. SMILEY 2,281,808

SWITCH Filed Feb. 4, 1941 Fig.2

214 1; avert-o1 WWLQZ Patented May 5, 1942 UNITED STATES PATENT OFFICESWITCH Gilbert Smiley, Hingham, Mass.

Application February 4, 1941, Serial No. 377,301

3 Claims.

The present invention relates to an electric switch and moreparticularly to a switch that may be operated by the elbow, knee, foot,or by bodily contact or the like. The invention more particularly ispreferably applied to the operation of electric switches in which themotion of the contact elements are extremely small, of the order ofseveral thousandths of an inch and 'in which the mechanism operated bythe foot, elbow or the like is also comparatively small.

The advantage of the present invention resides in the constructionalfeatures of the article whereby small switches which are often calledmicroswitches may be operated simply, positively and by means which ifdirectlyapplied to the switch unit itself may be of such a nature thatthese units would not stand up.

The present invention will be more fully understood from the descriptionin the specification below when taken in connection with the drawing, inwhich:

Figure 1 shows a sectional elevation of the clevice, and,

Figure 2 shows a plan view of a detail shown in Figure 1.

In Figure 1, i represents a casing which may be of metal or durablefiber material of rugged construction and comparatively substantialweight. 2 is an inlet for the electric cables, and 3 represents afriction plate so that the casing may remain fixed even though it is notscrewed down to the base member. 4 is a top plate which may be held downto the sides of the casing I by means of one or more screws 5 which passthrough the sides of the easing into a dependent fiange 6 from the topcover 4. A bracket or wall support I also projects downward from thecover t and this support I holds the microswitch 8 by means of the studsand bolts 9 and M respectively. The operating pin ll of the microswitchprojects through a shell or tube I! from the unit 8 which shell or tubeextends upward slightly beyond the top surface of the cover 4. A springi3 shown in plan in Figure 2 is symmetrically centered about the shelll2 which projects through a hole I4 in the center of the spring which isa fiat leaf spring with three projecting leaves l5, l6 and [1. Theseprojecting leaves are bent upwards and come in contact with the bottomof the operating plate l8, which plate the spring l8 freely supports.The plate I8 is held in position so that it cannot be removed from thecover 4 by means of the studs H which have large heads 20 abutting theinside of the cover placed with respect to the center tube l2. Thesestuds l9 work up and down in holes 2| which are sufficiently larger thanthe studs ill to permit free motion of the studs, at the same timemaintaining the motion of the plate up and down, but not parallelparticularly to the cover 4. The plate I8 may have a cover surface 22 ofrubber or other suitable material to provide easy contact and insureagainst friction in the operation of the switch.

The drawing shown in Figure 1 may be considered approximately full size,the spacing between the operating plate l8 and the cover plate 4 beingapproximately one eighth of an inch.

The switch as above described may be operated by pressure at any pointon the top of the operating plate on the member 22. The motion of thecover plate under these conditions is such that even when the plate isforced down at the edge, the center of the plate over the pin 'II willforce the pin downward the necessary distance for operation.

It will be noticed in the construction, the shell l2 projects beyond thesurface of the cover 4 of the casing approximately no more than thethickness of the spring l3, and that the pin H within the shell projectsa short distance beyond the shell so that the distance between the topof the pin and the operating cover or plate is considerably less thanthe distance between the cover plate 4 and the plate i8.

Further it should be noted that the pin H can be driven down flush withthe top of the shell or spring because of an overtravel mechanismcontained within these microswitches so that the pressure or weight onthe plate 10 will be borne by the shell it.

As indicated in Figure 1 these distances are in the ratio ofapproximately 2 to i. The pin ii is operated by a very slight motion andthis motion is obtainable by pressing the top cover at any point on itssurface in the same amount.

Having now described my invention, I claim:

1. In combination a comparatively heavy casing, a switch having anoperating pin operative by a longitudinal travel in the direction of thepin of the order of a small fraction of an inch, means suspending saidswitch within said casing in a position with the operating pinprojecting from the top of the casing, a protective collar surroundingthe operating pin, a leaf spring having more than two branches extendingfrom the center hub, said center hub having a perforation through whichsaid projecting collar extends, said 4. The studs l9 are preferablysymmetrically spring t t hub resting against said casing, a

plate positioned in parallel relationship over the top of the casing injuxtaposition with said operating pin and supported by the free ends ofsaid spring and means directing travel of said plate within limits toand from the direction of the top of the casing.

2. In combination a comparatively heavy casing, a switch having anoperating pin operative by a longitudinal travel in the direction of thepin oi the order ofa small fraction of an inch, means suspending saidswitch within said casing in a position with the operating pinprojecting from the top of the casing, a protective collar surroundingthe operating pin, a leaf spring having more than two branches extendingfrom the center hub, said center hub having a perforation through whichsaid projecting collar extends, said spring at its hub resting againstsaid casing, a plate positioned in parallel relationship.

over the top of the casing in juxtaposition with said operating pin andsupported by the free ends of said spring and a plurality of studsextending from the plate through perforations in the top of the casing,said perforations being larger than said studs to permit comparativelyiree motion of the studs through said perforations, said studs havingenlarged heads at the insideoi said cas- 111g, I

3. In combination a comparatively heavy casing, a switch having anoperating pin operative by a longitudinal travel" in the direction ofthe pin of the order of a small fraction oi! an inch, means suspendingsaid switch within said casing in a position with the operating pinprojecting through the top of the casing, a leaf spring having more thantwo branches and having a central hub with a perforation locatedtherein, means centering said spring with the perforation located oversaid pin, said spring at its hub resting against said casing, a platepositioned in parallel relationship over the top of the casing injuxtaposition with said operating pin and supported by the free ends ofthe spring and means directing the travel of said plate within limits toand from the direction of the top of the casing.

GILBERT SMILEY.

